EXPLANATIONS OF PLATE II, continued. 

 Climacograptus (sub-genus Dicranograptus) ramosus. 



( QraptoUthus ramosus, Palaeontology of New- York, Vol. i, page 27, and Geology of Canada, 



page 200.) 



Fig. 18. The lower part of a frond in which the base is entire, with the bifurcation 

 above (natural size). 



" 19. The bifurcating portion, with a part of the simple stipe, showing the cells on 

 one side as they are usually seen when flattened in the slate. On one por- 

 tion of this there are oval pustules, which is a feature sometimes observed. 

 The opposite side gives the appearance of the cellules when flattened and 

 compressed, partially against the aperture (six diameters). 



" 20. An enlargement from below the bifurcation, showing the more perfect form of 

 the aperture, with the spines proceeding from the exterior surface above 

 the aperture (enlarged to six diameters). 



" 21. A young individual or germ, supposed to be of this species, showing the basal 

 processes and the partially developed cellules at the upper part. 



